Clinically healthy subjects were selected: 19 with UAE >90th percentile in the background population (6.6 microgram/min

We have screened 397 chemicals for human androgen receptor (AR) antagonism by a sensitive reporter gene assay to generate data for the development of a quantitative structure-activity relationship (QSAR) model. A total of 523 chemicals comprising data on 292 chemicals from our laboratory and data on 231 chemicals from the literature constituted the training set for the model. The chemicals were selected with the purpose of representing a wide range of chemical structures (e.g., organochlorines and polycyclic aromatic hydrocarbons) and various functions (e.g., natural hormones, pesticides, plastizicers, plastic additives, brominated flame retardants, and roast mutagens). In addition, the intention was to obtain an equal number of positive and negative chemicals. Among our own data for the training set, 45.7% exhibited inhibitory activity against the transcriptional activity induced by the synthetic androgen R1881. The MultiCASE expert system was used to construct a QSAR model for AR antagonizing potential. A “5 Times, 2-Fold 50% Cross Validation” of the model showed a sensitivity of 64%, a specificity of 84%, and a concordance of 76%. Data for 102 chemicals were generated for an external validation of the model resulting in a sensitivity of 57%, a specificity of 98%, and a concordance of 92% of the model. The model was run on a set of 176103 chemicals, and 47% were within the domain of the model. Approximately 8% of chemicals was predicted active for AR antagonism. We conclude that the predictability of the global QSAR model for this end point is good. This most comprehensive QSAR model may become a valuable tool for screening large numbers of chemicals for AR antagonism.

Flow cytometric DNA analysis is an attractive alternative to conventional cytogenetics for diagnosing karyotype changes resulting in abnormal DNA content. We have developed methods for long-term storage of samples and standards, for staining the cells and for standardization of the measurements by two internal standards. In this paper the currently attainable resolution was determined and limiting factors were identified. Normal reference values for male and female leucocytes were determined by analyzing 240 samples from six men and six women, all cytogenetically normal. The DNA content of female cells was 1.5% higher than that of male cells. This finding was used to correct the results for sex related DNA differences. The 95% confidence limits for mononuclear blood cells were 20.79%. The results on granulocytes were exceptionally variable, with 95% confidence limits of k1.798. Reexamination of the normal leucocytes after 1 year showed a long-term drift of up to 2% in the results, indicating a need for regular checks of the reference values. In addition to the sex related differences in DNA content, individual differences of up to 1% were demonstrated. This creates problems as to which reference value to use for a particular sample. Furthermore, tissue related differences in fluorescence were found when six different tissues from one mouse were examined. The means had a range of 0.7%. The tissue related differences add uncertainty to the interpretation of the results. The resolution of heterogeneous populations with slightly different DNA content was examined by analyzing mixtures of cells with known DNA differences ranging from 1.50% to 5.83%. With a coefficient of variation of the peaks of about 2% a DNA difference of approximately 4% was required for accurate determination of the DNA content of the two individual populations. A lower coefficient of variation would increase the resolution, but tissue related differences in fluorescence could then become the limiting factor. To perform reliable analyses on a large-scale routine basis, a number of problems must be solved. We have developed methods for long-term storage of samples and standards (19), for fluorochrome staining of the cells (20) and for standardization of the measurements (21). The methods were designed to make sample collection independent of immediate subsequent analysis, and to make the results directly comparable irrespective of the day of analysis and eventually of the laboratory where the analysis is performed.In this paper the detection limits of these methods were determined and some limiting factors were identified. The strategy for testing the achievable resolution was to exploit the small sex and species related DNA differences in man and mouse. Materials and MethodsHuman leucocytes were separated into granulocytes and mononuclear cells by the method of Boyum (3). Cells from mouse liver, spleen, kidney and thymus were obtained by fine-needle aspiration (18). Mouse bone marrow from the femur and blood from the femoral artery were used. Ce...

Disease associated balanced chromosomal rearrangements (DBCRs), which truncate, delete, or otherwise inactivate specific genes, have been instrumental for positional cloning of many disease genes. A network of cytogenetic laboratories, Mendelian Cytogenetics Network (MCN), has been established to facilitate the identification and mapping of DBCRs. To get an estimate of the potential of this approach, we surveyed all cytogenetic archives in Denmark and southern Sweden, with a population of ∼6.6 million. The nine laboratories have performed 71 739 postnatal cytogenetic tests. Excluding Robertsonian translocations and chromosome 9 inversions, we identified 216 DBCRs (∼0.3%), including a minimum estimate of 114 de novo reciprocal translocations (0.16%) and eight de novo inversions (0.01%). Altogether, this is six times more frequent than in the general population, suggesting a causal relationship with the traits involved in most of these cases. Of the identified cases, only 25 (12%) have been published, including 12 cases with known syndromes and 13 cases with unspecified mental retardation/congenital malformations. The remaining DBCRs were associated with a plethora of traits including mental retardation, dysmorphic features, major congenital malformations, autism, and male and female infertility. Several of the unpublished DBCRs defined candidate breakpoints for nailpatella, Prader-Willi, and Schmidt syndromes, ataxia, and ulna aplasia. The implication of the survey is apparent when compared with MCN; altogether, the 292 participating laboratories have performed >2.5 million postnatal analyses, with an estimated ∼7500 DBCRs stored in their archives, of which more than half might be causative mutations. In addition, an estimated 450-500 novel cases should be detected each year. Our data illustrate that DBCRs and MCN are resources for large scale establishment of phenotypegenotype relationships in man. (J Med Genet 2000;37:858-865)

Cytogenetic studies of 91 consecutive patients with therapy-related myelodysplasia or overt acute nonlymphocytic leukemia disclosed characteristic defects of chromosome 7 in 48 cases and of chromosome 5 in 21 cases. The chromosome 5 abnormalities were consistently present in all abnormal mitoses at the time of diagnosis, as were the chromosome 7 abnormalities in 45 of the 48 patients. Various abnormalities, primarily of the short arm of chromosome 17, were observed in 13 cases, abnormalities of the long arm of chromosome 21 were observed in 12 cases, and rearrangements of 11q23 were seen in nine cases. Thirteen patients presented a normal karyotype. Previous therapy with alkylating agents, the presence of an initial myelodysplastic phase, and abnormalities of chromosome 7 or 5 were interdependent. Patients with 11q23 rearrangement typically developed overt leukemia of FAB types M4 or M5a without myelodysplasia and with a short latent period. Evaluated by Cox regression analysis, complete remission of the primary malignancy and a malignant lymphoma as primary tumor were the two most important and independent prognostic factors indicating a longer survival (P = .008). In addition, the platelet count at diagnosis was a significant prognostic factor (P = .01). For the subgroup of 62 patients with myelodysplasia, the number of chromosome aberrations, the percentage of blasts in the bone marrow, and the hemoglobin level were other significant and independent prognostic factors (P = .05, .05, and .004, respectively). The most important predictive factor for a favorable response to intensive antileukemic chemotherapy in overt leukemia was the absence of a preceding myelodysplastic phase (P = .0014).